1. Field of the Invention
The invention relates to a fuel injection system for a multi-cylinder internal combustion engine.
2. Description of the Prior Art
DE 100 60 785 A1 relates to a fuel injection apparatus equipped with a high-pressure fuel accumulator. Branch lines can be screwed to the high-pressure fuel accumulator, each containing a throttle for reducing pressure pulsations in the fuel injection apparatus. The throttles are each composed of a tube element that is either mounted to an end of the branch line to which a connecting head is attached or is accommodated inside the branch line, close to that end. Throttle elements in high-pressure accumulators (common rails) are used for pressure wave damping inside the body of the high-pressure accumulator. To achieve this, for example cylindrical throttle elements are press-fitted into connecting bores of the high-pressure accumulator (common rail) that lead to the individual fuel injectors or also to the high-pressure pump acting on the high-pressure accumulator. The throttle elements press-fitted into the connecting bores serve to improve the damping of pressure pulsations inside the fuel injection system, thus permitting an increase in the pressure-tightness of the individual components.
DE 20 2004 019 820.7 relates to a fuel injection apparatus for a diesel engine. A fuel injection apparatus includes a high-pressure fuel accumulator and a number of branch lines serving to convey fuel out of the high-pressure fuel accumulator. These branch lines each have a connecting head at their one respective end for connecting the branch line to an associated connection fitting of the high-pressure fuel accumulator, while a throttle is mounted in each of the branch lines. The throttle is embodied in a support element that is mounted in the region of the connecting head by means of attaching elements, which are embodied with the same design as the connecting head and which narrow an internal diameter of the branch line at the two ends of the support element. The throttle is provided in the support element and is embodied in the form of a through bore with a first partial bore and a second partial bore, i.e. it has two stages. During the upsetting of the connecting head, the through bore is protected by a stepped, cylindrical inner mandrel that is inserted into it and is embodied as recoverable. The support element preferably has a cylindrical circumference surface.
In internal combustion engines with six and more cylinders, two high-pressure accumulators are used, each of which supplies fuel to the fuel injectors of the cylinders of a respective cylinder bank. The two high-pressure accumulators (common rails) are connected to each other by a connecting line that provides for a pressure compensation between the high-pressure accumulators. In order to damp the pressure pulsations that occur in the two high-pressure accumulators, it is also possible for a distributor block to be provided. The distributor block is acted on by a high-pressure pump that compresses the fuel to the system pressure and maintains this system pressure in the two high-pressure accumulators. The two high-pressure accumulators are supplied with fuel by the distributor block, which is acted on by the high-pressure pump and in which pulsations are damped.